Patent GB-383835-A (GB)
Title: Improvements in and relating to the art of scanning and reproducing printed matter in embossed form
IPC: B41J3/32
Filed: 1932-03-04
Abstract: 383,835. Copying-telegraphy. NAUMBURG, R. E., 40, Meadow Way, Cambridge, Massachusetts, U.S.A. March 4, 1932, No. 6578. Convention date, April 10, 1931. [Class 40 (iii).] A method of reproducing printed matter in a form particularly suitable for touch reading by blind persons comprises the use of current variations produced by scanning successive sections of the matter with light rays tracing the sections along parallel paths, characterized by holding sheet material so that it may be indented from one side to form raised characters on the other side, the indentations being produced in response to the current variations, while the sheet material is moved relatively to the indentation means so that the indentations are punched in parallel rows corresponding to the parallel paths traced by the light rays. Light from a source 12, Fig. 1, passes through a system of lenses &c. adjustably mounted to accommodate letters of different sizes and a scanning disc 18 to be reflected from the printed matter 2 on to a selenium cell 21, Fig. 6. The continuously rotating scanning disc 18, Figs. 1 and 3, breaks the incident light into six intermittent beams which fall on the printed page along lines a .. f spaced to intersect the letters, as shown, by means of six rows of perforations, those of each row being staggered transversely. The selenium cell 21, Fig. 6, is connected through an amplifier to a circuit containing transformer primaries A .. F corresponding to the lines a . f of Fig. 3. With each primary is associated a secondary circuit tuned to one of the frequencies determined bv the number of perforations in each row of the scanning disc, one such secondary being shown in association with the primary A. Each of the six secondary circuits comprises a circuit as shown and a relay preferably of the trigger type through which the corresponding magnet 28a is operated, six magnets being provided, each operating a striker which serves to indent the sheet material S, Fig. 5. When the scanning rays are incident on white paper, the current in the magnets 28a is a maximum and the strikers are retracted, but when a printed line interrupts any of the incident beams, the current in the appropriate magnet is reduced and the striker advances under the action of a spring to make an indentation. The printed matter 2 in book form is mounted on a support 1 which carries a half nut 4 meshing with a worm 5 for advancing the book line by line by means of a ratchet handle 6. The scanning mechanism is mounted on a carriage 7 reciprocated along a stationary guide 8 by a rack 9 on the carriage which meshes with a pinion 10 on a shaft 11, and the reproducing mechanism comprising the six magnets and their associated strikers is mounted on a carriage 23 reciprocated on guides 25 by an arm 26 on the carriage which is threaded to mesh with a worm 27. The shaft 11 is connected to the worm 27 by gearing 56 and a clutch 57 and the worm 27 is driven from a motor 51 by a friction disc 54 on the worm which co-operates with a friction roller 55 driven by the motor.. The roller 55 has two limiting positions, one near the centre of the disc and the other at its edge, and the motor is reversible, means being provided for stopping and reversing the motor at the end of the reciprocatory movement of the carriages. While these are advancing from left to right, the roller 55 engages the disc 54 near its periphery, but to produce a quick return of the carriage on reverse of the motor the roller 55 is automatically moved to engage near the centre of the disc 54. The sheet material S which is to be indented is fed upwards and rearwardly over a guide 35, Fig. 5, having a slot 36 for the strikers, by means of rollers 37, 38, the roller 37 being driven by a ratchet thereon and a pawl on a rod 49 which is connected to linkage 48 and the handle 6. During the impression, the material S is held taut by pads 42, 43, both of which are carried by a shaft 41 ; both pressure pads are thus raised by rotating the shaft 41, and this is effected by the rotation of the handle 6. The reproducing carriage is preferably advanced faster than the scanning carriage and in order to increase the spacing still further, the strikers move in longitudinal slots so that they may lag behind the carriage until withdrawn by the current flow when they snap forward into normal position under spring action. The sheet material S is preferably aluminium or other metal foil, having minute protuberances to prevent tearing upon indentation, and the record formed may be erased by ironing out or rendered permanent by applying shellac, plastic wood, tilc cement in plastic wood solvent or the like. Instead of foil, a fine mesh screen may be used comprising several superposed sheets of screening with pins fitting in the perforations so that they may be engaged and projected by the strikers. The foil or screen may take the form of an endless belt which is rolled in advance of the striker path for repeated use. The width of the sheet S is preferably less than the total reciprocatory path of the strikers so that the latter are exposed beyond the sheet for setting before any line is embossed and in order that the strikers may not operate on the return of the carriage a shutter is caused to swing in front of the selenium cell as soon as the return movement commences.